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1.
Clin. Infect. Dis. ; 5(70): 850-858, 20200301.
Article in English | ELSEVIER | ID: covidwho-326398

ABSTRACT

Background. Respiratory virus-laden particles are commonly detected in the exhaled breath of symptomatic patients or in air sampled from healthcare settings. However, the temporal relationship of detecting virus-laden particles at nonhealthcare locations vs surveillance data obtained by conventional means has not been fully assessed. Methods. From October 2016 to June 2018, air was sampled weekly from a university campus in Hong Kong. Viral genomes were detected and quantified by real-time reverse-transcription polymerase chain reaction. Logistic regression models were fitted to examine the adjusted odds ratios (aORs) of ecological and environmental factors associated with the detection of virus-laden airborne particles. Results. Influenza A (16.9% [117/694]) and influenza B (4.5% [31/694]) viruses were detected at higher frequencies in air than rhinovirus (2.2% [6/270]), respiratory syncytial virus (0.4% [1/270]), or human coronaviruses (0% [0/270]). Multivariate analyses showed that increased crowdedness (aOR, 2.3 [95% confidence interval {CI}, 1.5-3.8]; P < .001) and higher indoor temperature (aOR, 1.2 [95% CI, 1.1-1.3]; P < .001) were associated with detection of influenza airborne particles, but absolute humidity was not (aOR, 0.9 [95% CI, .7-1.1]; P = .213). Higher copies of influenza viral genome were detected from airborne particles >4 μm in spring and <1 μm in autumn. Influenza A(H3N2) and influenza B viruses that caused epidemics during the study period were detected in air prior to observing increased influenza activities in the community. Conclusions. Air sampling as a surveillance tool for monitoring influenza activity at public locations may provide early detection signals on influenza viruses that circulate in the community.

2.
Nature ; 583(7818): 834-838, 2020 07.
Article in English | MEDLINE | ID: covidwho-261141

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus with high nucleotide identity to SARS-CoV and to SARS-related coronaviruses that have been detected in horseshoe bats, has spread across the world and had a global effect on healthcare systems and economies1,2. A suitable small animal model is needed to support the development of vaccines and therapies. Here we report the pathogenesis and transmissibility of SARS-CoV-2 in golden (Syrian) hamsters (Mesocricetus auratus). Immunohistochemistry assay demonstrated the presence of viral antigens in nasal mucosa, bronchial epithelial cells and areas of lung consolidation on days 2 and 5 after inoculation with SARS-CoV-2, followed by rapid viral clearance and pneumocyte hyperplasia at 7 days after inoculation. We also found viral antigens in epithelial cells of the duodenum, and detected viral RNA in faeces. Notably, SARS-CoV-2 was transmitted efficiently from inoculated hamsters to naive hamsters by direct contact and via aerosols. Transmission via fomites in soiled cages was not as efficient. Although viral RNA was continuously detected in the nasal washes of inoculated hamsters for 14 days, the communicable period was short and correlated with the detection of infectious virus but not viral RNA. Inoculated and naturally infected hamsters showed apparent weight loss on days 6-7 post-inoculation or post-contact; all hamsters returned to their original weight within 14 days and developed neutralizing antibodies. Our results suggest that features associated with SARS-CoV-2 infection in golden hamsters resemble those found in humans with mild SARS-CoV-2 infections.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/transmission , Coronavirus Infections/virology , Disease Models, Animal , Lung/pathology , Lung/virology , Mesocricetus/virology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Aerosols , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/virology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigens, Viral/immunology , Antigens, Viral/isolation & purification , Antigens, Viral/metabolism , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , Betacoronavirus/metabolism , Bronchi/pathology , Bronchi/virology , Coronavirus Infections/immunology , Duodenum/virology , Fomites/virology , Housing, Animal , Kidney/virology , Male , Mesocricetus/immunology , Nasal Mucosa/virology , Pandemics , Pneumonia, Viral/immunology , RNA, Viral/analysis , Viral Load , Weight Loss
3.
Nat Med ; 26(5): 676-680, 2020 05.
Article in English | MEDLINE | ID: covidwho-203367

ABSTRACT

We identified seasonal human coronaviruses, influenza viruses and rhinoviruses in exhaled breath and coughs of children and adults with acute respiratory illness. Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets. Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.


Subject(s)
Coronavirus Infections/transmission , Masks/virology , Pneumonia, Viral/transmission , Respiratory Tract Infections/transmission , Aerosols/isolation & purification , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Exhalation/physiology , Humans , Orthomyxoviridae/isolation & purification , Orthomyxoviridae/pathogenicity , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/virology , RNA, Viral/isolation & purification , Respiratory Tract Infections/pathology , Respiratory Tract Infections/virology , Virus Shedding
4.
Antiviral Res ; 178: 104786, 2020 06.
Article in English | MEDLINE | ID: covidwho-30820

ABSTRACT

An escalating pandemic by the novel SARS-CoV-2 virus is impacting global health and effective therapeutic options are urgently needed. We evaluated the in vitro antiviral effect of compounds that were previously reported to inhibit coronavirus replication and compounds that are currently under evaluation in clinical trials for SARS-CoV-2 patients. We report the antiviral effect of remdesivir, lopinavir, homorringtonine, and emetine against SARS-CoV-2 virus in Vero E6 cells with the estimated 50% effective concentration at 23.15 µM, 26.63 µM, 2.55 µM and 0.46 µM, respectively. Ribavirin or favipiravir that are currently evaluated under clinical trials showed no inhibition at 100 µM. Synergy between remdesivir and emetine was observed, and remdesivir at 6.25 µM in combination with emetine at 0.195 µM may achieve 64.9% inhibition in viral yield. Combinational therapy may help to reduce the effective concentration of compounds below the therapeutic plasma concentrations and provide better clinical benefits.


Subject(s)
Antimetabolites/pharmacology , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Emetine/pharmacology , Homoharringtonine/pharmacology , Lopinavir/pharmacology , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Virus Replication/drug effects , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Amides/pharmacology , Animals , Betacoronavirus/physiology , Chlorocebus aethiops , Drug Combinations , Epithelial Cells , Humans , Pandemics , Pyrazines/pharmacology , Ribavirin/pharmacology , Vero Cells
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